PHP基于循环的XML文档过滤

Question

I'm trying to filter out each XML category string of a specific category. How would I get this working?

For example I just want the x elements from the category Category1.

Example XML:

<store id="1" name="store">
    <species name="stud">
        <Category1 name="Category1">
            <x category="Hairs" id="20098288"/>
            <x category="Hairs" id="20098289"/>
        </Category1>
        <Category2 name="Category2">
            <x category="Shirts" id="24342342"/>
            <x category="Shirts" id="24342342"/>
        </Category2>
        <Category3 name="Category3">
            <x category="Jackets" id="423423423"/>
            <x category="Jackets" id="423423423"/>
        </Category3>
    </species>
</store>

My actual code, which would let me access every category's child elements:

<?php

    foreach($xmlDocument->species as $species_elem){
        foreach($species_elem->attributes() as $child){
            foreach ($child->x as $item){
                $itemID = $item->attributes()->id;
            }
        }
    }

?>

But I want to specify a Category which only should be access able. For example

$category = 'Category1';

Pseudo code:

<?php

foreach($species as $species_elem){
    foreach($species_elem which contains $Category1 as $category){
        foreach ($child->x as $item){
            $itemID = $item->attributes()->id;
        }
    }
}

?>

Answer 1

XPath will save you a lot of nested loops.

---

Example:

//$xml = your xml string;
$category = 'Category1';

$dom = new DOMDocument();
$dom->loadXML($xml);
$xpath = new DOMXPath($dom);

foreach ($xpath->query("/store/species/$category/x") as $node) {
    echo $dom->saveXML($node), "
";
}

---

Output:

<x category="Hairs" id="20098288"/>
<x category="Hairs" id="20098289"/>

---

This is done with PHP's DOM extension, but you can do the same basic thing with SimpleXMLElement::xpath if you really want to.